ES2956271T3 - Implantable stimulation power receiver and systems - Google Patents

Abstract

A wireless implantable neuromuscular stimulator includes an antenna for producing an induced current in response to being placed in an electromagnetic field. The antenna includes a substrate having a top surface and a bottom surface. An upper coil including a plurality of coil turns is disposed on the upper surface of the substrate. A bottom coil including a plurality of coil turns is disposed on the bottom surface of the substrate. The upper and lower coils are electrically connected to each other in parallel. Parallel connection may be facilitated by a plurality of connectors that extend through the substrate and electrically connect the upper coil to the lower coil. In an example configuration, the connectors connect each turn of the upper coil to a corresponding turn of the lower coil. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Implantable stimulation power receiver and systems

Technical field

An implantable electrical stimulation system and device are provided herein. More specifically, the present disclosure relates to an implantable stimulator that includes an antenna for powering the stimulator through inductive coupling with an external controller. In one example, the stimulator can be implemented in, or form part of, a system, method and apparatus for stimulating the hypoglossal nerve in order to treat obstructive sleep apnea.

Background

Obstructive sleep apnea (OSA) is the most common type of sleep apnea and is characterized by repeated episodes of complete or partial obstructions of the upper airway during sleep, despite effort to breathe, and is usually associated with a reduction in blood oxygen saturation. People with OSA are rarely aware of their shortness of breath, even upon waking. It is usually recognized as a problem by other people who observe the individual during the episodes or its existence is suspected due to its effects on the body. OSA is often accompanied by snoring. OSA may be associated with daytime symptoms (e.g., excessive daytime sleepiness, decreased cognitive functions). Symptoms may be present for years or even decades without being identified, and during that time the person may be affected by daytime sleepiness and fatigue associated with significant levels of sleep disturbance. People who generally sleep alone are not usually aware of the disorder, as they do not regularly share a bed with someone who can notice and warn them of the signs.

The current most widely used therapeutic intervention to treat OSA is positive airway pressure, in which a respirator pumps a controlled flow of air through a mask that is placed over the nose, mouth, or both. The added pressure keeps the relaxed muscles open. There are several mechanisms for the treatment of OSA with positive airway pressure. The most common treatment involves the use of continuous positive airway pressure (CPAP) machines. The OSA patient uses this CPAP machine at night while sleeping, putting on a mask connected by a tube to an air pump that maintains positive pressure in the airways.

Neurostimulation therapy may be an alternative for patients who cannot use a continuous positive airway pressure device. A neurostimulation system detects breathing and delivers mild electrical stimulation to the hypoglossal nerve (HNH) in order to increase muscle tone at the back of the tongue so that it does not sink into the airway. The NHG innervates the muscles of the tongue. It provides motor control to the muscles of the tongue and contributes to important voluntary and involuntary functions such as swallowing, speaking and chewing. Stimulation of the NHG can restore tone to the major muscles of the tongue which, when relaxed, can cause obstructive sleep apnea.

Conventional NHG neurostimulation systems use stimulation leads implanted in the patient's neck/throat, with electrodes in contact with the NHG, for example a cuff electrode surrounding or in close proximity to the NHG. The leads are connected to a pulse generator implanted under the skin on the patient's chest. From time to time, the pulse generator is surgically accessed to change the battery. The system includes a manual patient controller that allows the system to be turned on before bed.

Although NHG neurostimulation therapy has been shown to be an effective treatment for OSA, the volume of conventional systems and the degree of invasiveness in system implantation, use, and maintenance are undesirable. US2010/280568 provides a wireless implantable stimulator according to the preamble of claim 1.

Summary

The invention is defined in claim 1. The methods disclosed below are not within the scope of the invention and are disclosed for illustrative purposes only. In one aspect, a wireless implantable stimulator is provided. The stimulator may comprise an antenna for producing an induced current by being disposed in an electromagnetic field. The antenna may comprise a substrate having an upper surface and a lower surface, an upper coil comprising a plurality of coil turns arranged on the upper surface of the substrate, and a lower coil comprising a plurality of coil turns arranged on the bottom surface of the substrate. The upper and lower coils can be electrically connected to each other in parallel.

Brief description of the illustrations

• Fig. 1 is a diagram illustrating an example configuration of an implantable stimulation system according to one aspect of the present disclosure.

• Fig. 2 is a schematic illustration of an implantable stimulator portion of an implantable stimulation system according to one aspect of the present disclosure.

• Fig. 3 is a cross-sectional view taken generally along line 3-3 of Fig. 2, illustrating a portion of the implantable stimulator antenna.

• Figs. 4-6 are schematic illustrations depicting flexible properties of an implantable stimulator according to one aspect of the present disclosure.

• Figs. 7-8 are schematic illustrations depicting an example configuration of a lead portion of an implantable stimulator in accordance with one aspect of the present disclosure.

• Figs. 9A-9B are schematic illustrations depicting an example configuration of an antenna portion of an implantable stimulator in accordance with an aspect of the present disclosure.

• Figs. 10A-10C are schematic illustrations depicting example configurations of a power mat portion of an electrical stimulation system in accordance with an aspect of the present invention.

Detailed description

As used herein with respect to a described item, the terms "a" and "the" include at least one or more of the described items, including combinations thereof, unless otherwise indicated. contrary. Additionally, the terms "or" and "and" refer to "and/or" and combinations thereof, unless otherwise indicated. By "substantially" it is meant that the shape or configuration of the described element need not have the described mathematically exact shape or configuration of the described element, but rather may have a shape or configuration that a person skilled in the art recognizes as general or approximately the same to the described shape or configuration of the described element. As used herein, "stimulate" or "modulate" in the context of neuromodulation includes the stimulation or inhibition of neural activity. A "patient" as described herein includes a mammal, such as a human.

The present disclosure relates to an implantable electrical stimulation system 10, which can be used to provide various electrical therapies, including neuromodulation therapies such as nerve and/or muscle stimulation. Stimulation can induce excitatory or inhibitory neural or muscle activity. Such therapies can be used at various suitable sites in a patient's anatomy. In an example implementation, system 10 can be used to treat sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA), through neuromodulation of the hypoglossal nerve (NHG).

Electrical stimulation system

With reference to Fig. 1, the system 10 may include an implantable stimulator 20 and an external controller 100. The controller 100 may power the stimulator 20 via electromagnetic induction. The stimulator 20 may include a power receiver 30 with an antenna 32. Electrical current may be induced in the antenna 32 when positioned above the power mat 112 of the controller 100, in an electric field produced by the transmitting antenna. of power 112. The antennas 112 and 32 can also facilitate communication between the controller 100 and the stimulator 20, respectively. This power/communication connection between stimulator 20 and controller 100 is generally shown by arrow 70 in Fig. 1.

The system 10 may also include a user interface 200 in the form of a computing platform 202 that runs a custom application that allows communication with the controller 100 wirelessly, as generally indicated by arrow 204. This may be done, for example , through radio communication, Bluetooth or WiFi. In the example configuration of Fig. 1, the computing platform 202 is a smartphone. However, the type of computing platform 202 may vary. For example, computing platform 202 may be a physician or patient platform. Each platform 202 may have a user-specific application or "app" installed, that is, a patient application or a doctor application. The doctor platform would have the doctor app installed and the patient platform would have the patient app installed. The patient application may allow the patient to execute certain commands necessary to control the operation of the stimulator 20, such as, for example, starting/stopping therapy, increasing/decreasing stimulation power or intensity, and selecting a stimulation program. In addition to the controls offered to the patient, the doctor's app can also allow the doctor to modify stimulation settings, such as pulse settings (patterns, duration, waveforms, etc.), stimulation rate, pulse settings, electrode amplitude and configurations, open and closed loop control settings, and adjustment parameters for the integrated software that controls therapy delivery during use.

As generally indicated by arrow 206, computing platform 202 may be connected (e.g., WiFi and/or LTE network) to the internet/cloud 208, facilitating communication 214 with a remote or cloud-based server 216. This allows the transfer of data between the server 216 and the computing platform 202 via internet 208. In addition, the controller 100 itself may also be connected to the internet (e.g., by WiFi), as shown at 210. This also may allow data transfer between controller 100 and server 216 over internet 208.

System communication

As shown in Fig. 1 and described above, system 10 can be configured to provide various communication paths between system components. For example, the computing platform 202 that is connected to the controller 100 (see 204) and the internet 208 (see 206) can provide a communication path from the remote server 216 (see 214) to the stimulator 20 itself (see 70). A communication path can also be established between the server 216 and the stimulator 20 through a WiFi connection 210 of the controller 100.

Additionally, recognizing that the physician may be remote from the patient, a path of communication with the physician may be established through the internet connection 206 of the remotely located physician platform 202. Through this connection, the remote doctor platform 202 can communicate with the server 216 through the Internet connection 206. The remote doctor platform 202 can also communicate with the controller 100, either through the Internet connection 210 (when enabled) or through patient controller 202.

In addition to facilitating local control of system 10, for example, controller 100 and stimulator 20, the various communication paths described above may also allow:

• Distribute from the server 216 software/firmware updates for the computing platform 202, the controller 100 and/or the stimulator 20.

• Download from the server 216 the therapy settings/parameters to be implemented by the computer platform 202, the controller 100 and/or the stimulator 20.

• Facilitate therapy setup/parameter adjustments/algorithm adjustments by a remotely located clinician.

• Upload data recorded during therapy sessions.

• Maintain consistency in settings/parameters by distributing changes and adjustments across all system components.

System Operation Overview

The therapeutic approach implemented with system 10 may involve implanting only the stimulator 20, leaving the controller 100 as an external component to be used only during the application of therapy. To facilitate this, the stimulator 20 may be configured to be powered by the controller 100 via electromagnetic induction. In operation, the power mat 110, driven by the control unit 120, can be placed outside the patient in the vicinity of the stimulator 20 to position the transmitting antenna 112 of the controller, located on the mat, near the receiving antenna 32 of the stimulator. In the implementation in which the system 10 is used to treat OSA, the power mat 110 can be placed on or sufficiently close to the sleeping surface while the patient sleeps to maintain the position of the receiving antenna 32 within the target volume of the field. electromagnetic generated by the feed antenna 112.

Through this approach, system 10 can deliver therapy to improve TRS such as OSA, for example, by stimulating NHG, for example, through a shorter and less invasive procedure. Eliminating an implanted power supply in favor of an inductive power scheme can eliminate the need for batteries and associated battery changes throughout the patient's life.

Additionally, the stimulator 20 may implement electromyography (EMG) electrodes to detect neuromuscular responses to the patient's physiological needs during sleep. These sensing electrodes can continuously monitor intrinsic physiological EMG signals of the anterior lingual musculature. For example, EMG sensing electrodes can be configured to detect neuromuscular responses from the genioglossus muscle, which is innervated by the NHG.

The controller 100 may use the transmit antenna 112 for multiple purposes, for example: 1) to provide power to the stimulator 20 during therapy sessions, and 2) to communicate with the stimulator. This communication may, for example, include programming, for example, uploading software/firmware revisions to the stimulator 20, changing/adjusting stimulation settings and/or parameters, and adjusting the parameters of the control algorithms. Controller 100 may receive programming, software/firmware, and settings/parameters through any of the communication paths described above, for example, from user interface 200 or through a WiFi connection to the Internet, when is available. The communication paths can also be used to download data from the stimulator 20, such as measured data relating to completed stimulation therapy sessions, to the controller 100. The controller 100 can transmit the data downloaded from the stimulator 20 to the controller 100, as data measured relative to completed stimulation therapy sessions. Controller 100 may transmit the downloaded data to user interface 200, which may send/upload the data to server 216 via internet 208.

During operation, EMG responses detected from the genioglossus muscle may allow closed loop operation of the stimulator 20, eliminating the need for a thoracic cable. Operating in closed loop, stimulator 20 can keep stimulation synchronized with breathing, for example, while preserving the ability to detect and address momentary obstruction. The stimulator 20 can also detect and respond to snoring, for example.

To facilitate real-time closed loop control, a control algorithm can be implemented locally on the stimulator 20. This can be achieved, for example, by programming a control algorithm into an application specific integrated circuit (ASIC) component of the stimulator. 20 (see below for description of the stimulator electronics).

Operating in real time, the stimulator 20 may record data related to the stimulation session including, for example, stimulation settings, EMG responses, respiration, sleep status including different phases of REM and non-REM sleep, etc. For example, changes in the phasic and tonic EMG activity of the Genioglossus muscle during inspiration can serve as a trigger for stimulation or changes in stimulation can be made based on changes in the phasic and tonic EMG activity of the Genioglossus muscle during inspiration. inspiration or during the different phases of sleep. After the sleep session, this recorded data can be uploaded to the user interface 200 and the server 216. Additionally, the patient may be asked to use the interface 200 to record data relating to their perceived sleep quality, which also can be uploaded to server 216. Offline, server 216 can run a software application to evaluate the recorded data and determine if control settings and parameters can be adjusted to further optimize stimulation therapy. The software application may, for example, include artificial intelligence (AI) models that learn from recorded therapy sessions how certain settings affect the therapeutic outcome for the patient. Thus, through AI learning, the model can provide optimized therapy specific to the patient.

Stimulator settings

The stimulator can have various configurations, which can be adapted to the specific therapy that is intended to be applied and/or to the anatomy of the point where the stimulation therapy is applied. An example configuration of the stimulator 20 is illustrated in Fig. 2. The stimulator 20 may include a power receiver 30, an electronic package 50, and a stimulator cable 80. The power receiver 30 may include a spiral receiving antenna 32 that It is packaged in a protective biocompatible material and is operatively connected to the electronic package 50 and the electronic components 52 mounted therein.

The stimulator cable 80 is also operatively connected to the electronic package 50, which controls the operation of the electrodes 82. In the example configuration of the present disclosure, the stimulator 20 includes a spiral connector 54, which extends from the electronic package 50. and may facilitate connection of the stimulator cable 80 to the electronic package. The coil connector 54 may facilitate a detachable connection between the electronic package 50 and the stimulator cable 80, so that cables of different configurations can be connected to the electronic package. This may facilitate the manufacturing of the stimulator lead 80. It may also allow the physician to select a lead that has the desired size and/or configuration.

Additionally, the stimulator lead 80, which is separate from the rest of the stimulator 20 and can be connected thereto through the coil connector 54, can facilitate implantation of the lead separately. As a result, lead 80 implantation can be much less invasive, allowing the lead to be placed through a small incision. An integrated design could require a larger incision and also the need to handle and manipulate the entire stimulator 20 as a whole during the implantation process, which could complicate lead placement as the surgeon may have to work around the rest. of the stimulator 20, for example, of the electronic package 50 and the antenna 32.

Stimulator cable 80 may be generally elongated and includes a plurality of electrodes 82 spaced along its length. The electrodes 82 may be electrically connected to the electronic package 50 by conductors, such as cables, which are schematically illustrated at 84 by dashed lines in Fig. 2. In the example configuration illustrated in Fig. 2, the stimulator 20 has a eight-channel, eight-electrode configuration, meaning that the stimulator cable 80 includes eight electrodes 82, each with its own specific channel. The stimulator 20 can be configured to have a greater or lesser number of channels. Additionally or alternatively, the stimulator 20 may include more than one cable, again depending on the particular therapy and/or the target anatomical structure. Regardless of the number of cables or channels, each electrode 82 can be configured and used independently of the other electrodes. Because of this, all or some of the electrodes 82, which are determine which is most effective for a particular application, they can be used during the application of stimulation therapy.

Electrodes 82 can be used as stimulation or detection electrodes. Stimulating electrodes can be used to apply stimulation to a target anatomical structure, such as a nerve or muscle. Sensing electrodes can be used to detect and measure an Mg response, for example, of a neuromuscular structure associated with the target nerve. For the application of a treatment for a TRS illustrated in this description, the target nerve may be the NHG and the associated muscle may be the genioglossus muscle. The stimulator can, however, be used to target other nerves and to measure physiological electrical signals from other anatomical structures, such as EMG responses, from other neuromuscular structures.

In the example configuration of Fig. 2, the electrodes 82 are arranged in two groups of four electrodes spaced along the length of the cable 80. One group of electrodes 82 may be placed distally near one end of the cable 80 and one group may be placed proximally between the distal group and the electronic package 50. However, the configuration of the electrodes 82 may vary. The stimulator may include a different number of electrodes (two or more), and/or the electrodes may be grouped, spaced, or otherwise arranged in different configurations along the cable. As mentioned above, the stimulator may also include any suitable number of leads (one or more).

The identity of the electrodes 82 as stimulation or sensing electrodes can be determined by the way they are controlled through the electronic package 50. In certain implementations, the identity of the electrodes 82 can be fixed. In a fixed implementation, some of the electrodes 82 may be assigned and used exclusively as stimulation electrodes and others may be assigned and used exclusively as sensing electrodes. In other implementations, the identity of the electrodes 82 may be dynamic. In a dynamic implementation, electrodes 82 can be assigned and used as stimulation and sensing electrodes. In other implementations, the electrodes 82 may be implemented in combinations of fixed and variable identities.

How the electrodes are used depends, at least in part, on how the stimulator itself is implemented. In certain implementations of the stimulator, some or all of the electrodes may be placed in relation to structures, such as nerves and/or muscles for which both the application of stimulation energy and the detection of a Mg response or other signal are desired. physiological electrical. In these cases, some or all of the electrodes can be used as stimulation electrodes when stimulation at their location is desired and as sensing electrodes when detection at their location is desired. In other implementations of the stimulator, some electrodes may be placed in relation to structures for which only the application of stimulation energy is desired and other electrodes may be placed in relation to structures for which only the detection of EMG responses or other physiological signals is desired. .

Advantageously, the identities of the electrodes 82 are configured in software settings and do not require hardware configurations. Selectable configurations of the electrodes 82 may be facilitated by the electronic components 52 included in the electronic package 50. The electronic components 52 are preferably implemented in an application specific integrated circuit (ASIC). The electronic components 52 may, however, include one or more ASICs, discrete electronic components, and electrical connectors for connecting the electronic components to the power receiver 30 and/or the electrode cable 80. The electronic components, whether incorporated into a single ASIC or in one or more components, may, for example, include processing and memory components, for example, microcomputers or computers on a chip, charge storage devices (for example, capacitors) to accumulate a charge and supply charging power stimulation, and solid-state switching devices to select electrode identities (e.g., anode, cathode, recording electrode) and modulate the power delivered to the electrodes (e.g., pulse width modulation (PWM) switches) ).

To provide patient comfort and ease of insertion for clinicians, the stimulator 20 may have a generally soft/flexible construction. This soft/flexible construction can be applied to the cable 80, the power receiver 30, or both the cable and the power receiver. In an example configuration, the components of the stimulator—power receiver 30, electronic package 50, and cable 80—can be coated or otherwise coated simultaneously in a single operation, such as insert molding with a biocompatible material, such as silicone, epoxy and various suitable polymers.

With respect to Figs. 4-6, the power receiver 30 and the cable 80 may have a flexible configuration that allows one or both structures to bend or flex, facilitating compatibility of the implantation with various anatomical structures. The power receiver 30 may be generally flat and planar in configuration, and may be bent in directions transverse to its plane which, as shown in Figs. 4-6, is the XY plane. Therefore, the power receiver 30 can be bent in the Z direction, as shown with dashed lines at 30' in the Figures. The cable 80 may generally have an elongated configuration and extend axially, along the X axis, as shown in Figs. 4-6. The wire 80 can be bent in multiple directions with respect to that plane, that is, in the Y or Z direction, or both, as shown with dashed lines at 80' in the figures.

To facilitate the flexible configuration of the cable 80, the electrodes 82 and the conductors 84 (see Fig. 2) that connect the electrodes to the electronic package 50 may be encapsulated and retained in a cover 86. The cover 86 may be formed of a material biocompatible, such as silicone and various suitable polymers, and can be configured to expose the electrodes 82 or part thereof. The cover 86 may be formed, for example, in said insert-molded cover of the stimulator structure 20.

To facilitate flexible configuration of the power receiver 30, the antenna 32 may be formed on a soft substrate to be flexible and conform to the anatomy of the implantation site. For example, the power receiver 30 may have a flexible printed circuit board (PCB) construction in which the antenna 32 is created from a thin layer of conductive metal laminated onto a substrate 38 (see Fig. 3). constructed of a flexible material, such as a polymer. In a particular flexible PCB construction, the substrate may be a polyamide material and the conductive metal may be copper. Other flexible PCB constructions can be implemented. The antenna 32 may be encapsulated and retained in the cover 48. The cover 48 may be formed of a biocompatible material, such as silicone, epoxy, and various suitable polymers. The cover 48 may be formed, for example, in said insert-molded cover of the entire structure of the stimulator 20.

The flexible PCB of the power receiver 30 may extend toward the electronic package 50 and may be configured for mounting the electronic components 52. The PCB may also be configured to interconnect the conductors 84 of the cable 80 and/or to form portions thereof. wire. In this case, the power receiver 30, the electronic package 50 and the cable 80 (or part thereof) may be coated with the biocompatible material (for example, silicone, epoxy and various suitable polymers) simultaneously.

Although flexible, the cable can also be configured to maintain the shape it has been given. This feature may, for example, be facilitated by conductors 84 connecting electrodes 82 to electronic package 50 or by an additional internal shape-maintaining support structure (e.g., metal) (not shown) extending along its longitude. In any case, the metal conductors 84 or the support structure can be selected or otherwise configured to have physical properties, such as malleability/ductility, that allow the cable to be manipulated three-dimensionally (3D) to give it a desired shape or to have a predetermined bias and maintain that shape or bias once formed. For example, the cable may be biased to have a certain shape to be created, for example, by heat forming, material forming, or using other methods of manufacturing a cable of a certain shape.

The Figs. 7-8 illustrate one of these 3D shapes that the cable 80 can take. The example configuration of Figs. 7-8 shows the cable 80 formed three-dimensionally in a generally "U" or "Q" shape, as shown in the plan view of Fig. 7, with an additional or alternative curvature in depth as shown in the Fig. 8. This particular 3D configuration can be implemented to place the electrodes 82 in different positions along the NHG, where the stimulator is configured to treat TRS, such as OSA, for example. More specifically, the configuration of cable 80 in Figs. 7 and 8 may allow the right and left electrodes 82 (as seen in Fig. 7) to be placed very close to the NHG branches. The right and left electrodes 82 in an implanted configuration may extend along the posterior-anterior course of the NHG, placing the electrodes at or near branch points, such as branch points distal to the main trunk. This placement allows direct electrical activation of one or more branches, as necessary for posterior airway control. Furthermore, with this implementation of lead 80, neurostimulation system 10 can be configured to stimulate bilaterally or unilaterally, as appropriate, without unnecessary or unwanted stimulation of surrounding structures. Due to the three-dimensional nature of cable 80 and the synchronous manner in which the anterior lingual muscle moves, additional anchoring structures may be unnecessary. For example, the lower curvature of the middle portion of the lead with respect to the left and right electrode assemblies 82 when the stimulator is fully deployed may allow the lead to exert force against the genioglossus muscle, since this muscle has a convex shape ( seen from below), to obtain better contact between the electrode assemblies and the genioglossus muscle.

The power receiver is designed with the objective of supplying maximum power to the stimulator from a given external magnetic field. With this goal in mind, for the NHG stimulation implementation of the example configuration disclosed herein, the power receiver 30 and receiving antenna 32 have a unique configuration designed to meet several criteria for the stimulator 20. The criteria They depend, of course, on the intended therapeutic use of the system and the resulting configuration. The criteria set forth below are specific to an example configuration of system 10 for the treatment of SDB, such as OSA, using NHG neuromodulation:

• Stimulator 20 operates within the maximum allowable magnetic field exposure guidelines recommended in IEEE C95.1-2005 (Reference 3).

• The receiving antenna 32 allows almost continuous power consumption (10-30 milliwatts (mW)) of the stimulator 20.

• The receiving antenna operates at a frequency between the ISM bands (industrial, scientific and medical radio bands of the radio frequency spectrum) of 100 kHz and 2.4 GHz. In one particular implementation, frequencies of 6.78 MHz were used or 13.56 MHz.

• The receiving antenna 32 has a diameter of 2-3 cm. and is as thin as possible to maintain flexibility.

• Stimulator 20 is small enough for minimally invasive subcutaneous implantation within the soft tissue of the submandibular region.

• The stimulator 20 maintains a soft and flexible design so that it can be manipulated and adjusted to the patient's anatomy.

Other stimulation therapies or implementations of the implantable stimulation system 10 may cause some or all of these criteria to be changed or adjusted, as well as certain criteria to be added or deleted.

To meet these criteria, the receiving antenna 32 may have a double layer planar pancake configuration. With respect to Fig. 3, the antenna 32 may have a flexible PCB construction in which the first / upper antenna coil 34 is formed on a first / upper side of the substrate 38 and the second / lower antenna coil 36 is formed on a second/lower side of the substrate. The substrate 38 may be a thin layer (e.g., 1 to 3 mil) of polyamide and the coils 34, 36 may be created from thin layers of copper or gold (e.g., 1 oz./ft2 "1, 4 mil) laminated onto substrate 38.

The PCB 38 may also retain electronic components 52 in the electronic package 50. Using the guidelines for maximum allowable magnetic field exposure, IEEE Standard C95.1-2005 (which is incorporated herein by reference in its entirety), the power maximum achievable delivered is approximately 10-30 mW at a frequency of 6.78 MHz. These power requirements were chosen based on the estimated requirements for the components 52 of the electronic package 50, the estimated maximum stimulation parameters and preclinical studies, while a safety factor was included to allow for capacitor charging and provide transition power. Transition power can be supplied by various components such as capacitors, supercapacitors, ultracapacitors, or even a rechargeable power source such as a battery. Continuous power during patient movement, especially at the higher end of power ratios and/or during engagement is not ideal. The transient power supply helps ensure full and continuous operation of the stimulator 20, even during patient movement.

Those skilled in the art will appreciate that, during operation, an antenna may be susceptible to power losses due to substrate losses and stray capacitance between coils 34, 36 and between individual coil turns. Substrate losses occur due to eddy currents associated with non-zero resistance of the substrate material. Stray capacitance occurs when these adjacent components are at different voltages, creating an electric field that results in a stored charge. All circuit elements have this internal capacitance, which can cause their behavior to deviate from that of "ideal" circuit elements.

Advantageously, the antenna 32 can implement a single two-layer pancake coil configuration in which the coils 34, 36 are configured in parallel. As a result, the coils 34, 36 can generate an equal or substantially equal induced voltage potential when subjected to an electromagnetic field. This can help equalize the voltage of the coils 34, 36 during use, and has been shown to significantly reduce the parasitic capacitance of the antenna 32. In this parallel coil configuration of the antenna 32, the upper and lower coils 34, 36 are shorted in each turn. This design has been found to maintain the advantage of lower series resistance in a two-layer design while greatly reducing stray capacitance and producing high maximum output power.

This improved parallel configuration of antenna 32 is illustrated in Figs. 9A and 9B, showing the upper and lower coils 34 and 36, respectively, on the PCB substrate 38. Each coil 34, 36 may include a plurality of coil windings or turns 40 and may be characterized by the following properties: number of turns (N), outer diameter (OD), coil pitch (P), trace width (AN) , trace thickness (ES), and coil spacing (ESP). These properties are measured as follows:

• The OD is the diameter of the coil 34, 36 measured across the coil between the outer edges of the outermost turn 40.

• The pitch P of the coil is the coil spacing 40 measured between any two adjacent coils.

• The width of the coil AN is the width of each turn of the coil 40.

• The thickness of the ES trace is the thickness of the turns 40, which is determined by the thickness of the conductive layers (Cu) laminated on the substrate 38 in the construction of the PCB.

• ESP coil spacing is the distance between coils 34, 36, which is determined by the thickness of the substrate 38 in the PCB construction.

In a particular configuration of the antenna 32, the PCB substrate 38 is a 2 mil layer of polyamide and the coils 34, 36 are formed from 1.4 mil copper laminated onto the substrate. The parallel coil configuration of the antenna 32 results from electrically connecting the turns 40 of the coils 34, 36 across the substrate 38. These connections may be in the form of electrically conductive connectors illustrated at 42 in Figs. 9A and 9B. The connectors 42 between the turns 40 can, for example, be formed by drilling or laser engraving holes through the PCB structure, for example, through the substrate 38 and the turns 40 of the upper and lower coils 34, 36, and plating or filling the holes with a metal, such as a copper/gold plate or molten tin-lead and/or fluid, for example, to electrically connect the turns of the opposite surfaces of the substrate. The connectors could also be formed mechanically, for example with pins or rivets.

The coils 34, 36 of the antenna 32 have a unique configuration that allows them to be interconnected in parallel. On each side of the antenna 32, the turns 40 are semicircular, each with a fixed diameter and ends very close to each other. This is opposed to a traditional coil configuration in which the diameter of the coils varies continuously in a spiral that progressively decreases from the outside to the inside. To create the antenna coil configuration 32, on one side of the antenna (top side of coil 34 in the example configuration of Fig. 9A), links 44 may extend diagonally between adjacent turns 40 of the top coil. 34. The links 44 may be formed as portions of the copper layer, for example, laminated onto the substrate 38, and therefore may be formed coextensively with the turns 40 of the top coil 34 as a continuous conductive strip (Cu). Therefore, the upper coil 34 can be configured as a continuous coil of decreasing diameter from the outside to the inside and, therefore, can function as a coil configured in a spiral.

On the side of the lower coil 36 of the antenna 32, the turns 40 may also be semicircular, each having a fixed diameter with ends very close to each other. There may be no links connecting adjacent turns 40 of the lower coil 36. Instead, on the side of the lower coil 36 of the antenna 32, terminals 46 may be formed, one connected to a terminal end of the innermost turn of the lower coil and another connected to a terminal end of the outermost turn of the lower coil. The terminals 46 may be connected to the innermost coil 40 and may extend into the space between the ends of the remaining coils.

Viewing Figs. 9A and 9B, the turns 40 of the upper and lower coils 34, 36 can be interconnected at each of the connectors 42. Through the connectors 42, the links 44 that interconnect the adjacent turns 40 of the upper coil 34 can also be interconnected. interconnect with the adjacent turns of the lower coil 36. Thus, the turns 40 of the lower coil 36 can also be arranged in a continuous wound configuration through the connectors 42 and the links 44. Therefore, the lower coil 36 can be configured as a continuous coil that has a decreasing diameter from the outside to the inside and can therefore function as a coil configured in a spiral.

The terminals 46 may be electrically connected to both the upper coil 34 and the lower coil 36 through connectors 42. The terminal ends from which the terminals 46 extend may be radially opposite ends of the inner and outer turns 40. As shown, the terminal 46 of the innermost coil 40 is connected to a first end of the coil, on a first side of the space between opposite ends of the coils; while the terminal of the outermost coil 40 is connected to a second opposite end of the coil, on a second opposite side of the space between the opposite ends of the coils.

For the configuration illustrated in Figs. 9A and 9B, antenna performance may depend on the properties listed above. Example configurations of the antenna were tested, for which some of these properties were adjusted. These example configurations are illustrated in the following table:

As shown in the table above, the maximum power delivered by each example coil configuration met or exceeded the 10-30 mW power requirement, even with the reduced coil outside diameter of Example 4.

The external controller 100 may have two components: the power mat 110 and the bedside control unit 120. The control unit 120 may be connected to the power mat 110 by cable, for example, and is designed to be placed next to the bed, for example, on a nightstand. The control unit may include a user interface, for example, buttons, knobs, touch screen, etc., to allow the user to control the operation of the system when used in bed. The power mat 110 may be designed to be placed on a sleeping surface, such as the mattress of a bed, and therefore may be configured to have the shape of a pad, for example, a thin, flat, soft, flexible and anti-slip. The power mat 110 supports one or more wireless power transmission coils 112 in or on a flexible or semi-flexible surface 114. The power mat 110 can be placed on the lying surface so that a bottom edge 116 of the mat approximately corresponds to the position of the patient's shoulders while sleeping. The shape and size of the power mat 110 can correspond, for example, to those of a pillow, such as an elongated pillow.

The control unit 120 may excite the power transmission coils 112 to generate an electromagnetic field. The external controller 100 may use the transmission coils 112 of the power mat 110 to provide wireless energy transfer associated with the stimulator 20 via the receiving antenna 32 by electromagnetic induction. When the patient is in the sleeping position on the sleeping surface, the antenna 32 of the stimulator 20 can be placed within the electromagnetic field produced by the transmission coils 112 of the power mat 110. The shape of the field can be adapted through the configuration of coils 112 to provide an optimized field to power the stimulator 20 in various sleep positions. For example, the field can be configured to extend horizontally (as seen in Figs. 10A-C) between the coils 112, so that the stimulator 20 can be powered any time it is located within the vertical limits. of the horizontally extending field.

Through induction, electrical current can be induced in the receiving antenna 32 and that current can be provided to the electronic package 50 of the stimulator. The components 52 of the electronic package 50 control the operation of the electrodes 82. Through this operation, the electrodes 82 can be used as stimulation electrodes to apply electrical stimulation to nerves or muscles, for example; as EMG sensing electrodes, for example, to detect a neuromuscular response to the application of electrical stimulation; or as both stimulation and detection electrodes at different times during the application of stimulation therapy.

In addition to providing power to the stimulator 20, the external controller 100 may also provide a data connection to facilitate bidirectional communication between the controller and the stimulator. While powering the stimulator, the controller 100 may simultaneously provide a wireless data signal that is used to program the stimulator with settings, such as electrode assignments and stimulation parameters, and also to retrieve stored data from the stimulator, such as triggered stimulation events, measured EMG responses or other physiological electrical signals, current values, electrode impedances and data related to wireless energy transfer between the controller 100 and the stimulator 20.

Additionally, the stimulator 20 may monitor the impedance and/or voltage of the stimulator antenna 32 in order to calculate the power delivered to the stimulator. This may be provided in the form of feedback to the controller 100 that allows the controller to adjust the current supplied to the power transmission coils 112. The controller 100 may control the power supplied to the stimulator so that it remains within the standards/requirements set forth above. At the same time, the feedback may also facilitate increasing the current supplied to the power transmission coils 112 so that adequate power transfer to the stimulator 20 is maintained, again within prescribed limits. In this way, the controller 100 can implement closed loop control to optimize the power delivered to the stimulator 20.

The operation of the controller 100 can be controlled through the user interface 200, which allows the user, for example, the patient, doctor or other caregiver, to control aspects of the operation of the implantable stimulation system 10. The control can be local, for example, by the patient through the user of the control unit 120 or the patient user interface 200, or remote, for example, by the doctor via the internet/cloud 208. The control unit 120 can take up little space and the power mat 110 can have a flexible design to make the external controller 100 small, discreet and portable for on the go.

Power mat configuration

To account for varying sleep positions throughout the night, the power mat 110 may be sized large enough to allow for patient movement while maintaining the ability to transmit energy to the stimulator 20. At the same time, the external controller 100 produces electromagnetic radiation at a level that falls outside the maximum allowable magnetic field exposure guidelines recommended in IEEE Standard C95.1-2005 (Reference 3).

In Figs. 10A-10C illustrate examples of drive coil configurations that can be implemented in the power mat 110. These example drive coil configurations can be implemented with a flexible circuit design, that is, the coils can be formed (e.g., created ) from a conductive metal (e.g. copper or gold) laminated to a flexible substrate (e.g. polyamide). The examples in Figs. 10A-10C illustrate the general shape of the transmission coils 112 without showing the individual turns thereof. This is because the properties of the transmission coils 112, for example, the number of turns, the pitch/spacing of the coils, the width of the trace, etc., are not limited, as may be the case with the coils 34, 36 of the antenna 32. The antenna coils 34, 36 may be specifically adapted for maximum induced power generation due to the limitations of the small size of the antenna 32 of the stimulator 20. The power mat 110 may be larger in comparison and the transmission coils 112 can be freely configured to produce a magnetic field that may be limited only by requiring a level that conforms to the magnetic field exposure guidelines of the IEEE standard mentioned above.

Accordingly, the transmission coils 112 can be configured to maximize the space or volume covered by the magnetic field to allow variations in the patient's position during sleep. This can give the system the ability to continuously power the stimulator through a variety of sleep positions throughout the night. Fig. 10A shows an example configuration of twelve transmission coils 112; Fig.10B shows an example configuration of two transmission coils; and Fig. 10C shows an example configuration of four drive coils. For all of these example configurations, experimental tests showed that the transmission coils 112 are capable of meeting the system power requirements, in accordance with the IEEE standard exposure guidelines, while allowing coherent power transmission at the antenna 32 in an effective volume of approximately 32 x 76 x 25 cm (L x W x H), which was considered sufficient to cover the patient during a normal sleep cycle.

The configuration of twelve transmission coils 112 of Fig. 10A may allow dynamic control of the magnetic field produced by the power mat 110. Through the data connection and communication between the external controller 100 and the stimulator 20, it can be Determine which coil(s) of the twelve coil configuration is(are) making the power connection between the external controller and the stimulator. Through this determination, the external controller 100 can power only those coils necessary to power the stimulator 20, given the current position of the patient relative to the power mat 110. As the patient changes position, the stimulator can detect any decrease in power transmission, which may trigger reevaluation and selection of different coil(s). Thus, this configuration can be self-adjusted on the fly to maximize the electromagnetic field produced by the power mat 110 in the antenna area 32.

The two coil configuration of the transmission coils 112 of Fig. 10B can have static power coils, which produce a continuous electromagnetic field around the power mat 110. This configuration can be adjusted to maximize the intensity of the electromagnetic field at the greatest possible volume, so that power transmission is maximized in a wide variety of patient positions.

In the example configurations of both Fig. 10A and Fig. 10B, the power mat 110 may have a flexible construction facilitated by a flexible circuit construction of the transmission coils 112 housed within a flexible cover, such as, e.g. For example, soft plastic, rubber, fabric, etc. The drive coils 112 may, for example, have a flexible PCB construction similar to the antenna 32 of the stimulator 20. For example, the drive coils 112 may be constructed in the form of a single-layer flexible PCB, with conductive traces. made of copper, for example, laminated on a polyamide substrate, for example.

Claims (15)

1. A wireless implantable stimulator comprising an antenna for producing an induced current in response to its arrangement in an electromagnetic field, wherein the antenna comprising a substrate having an upper surface and a lower surface, an upper coil comprising a plurality of coil turns, and a lower coil comprising a plurality of coil turns, where the upper and lower coils are electrically connected to each other in parallel, and are characterized in that the upper coil is arranged on the upper surface of the substrate and the lower coil It is arranged on the lower surface of the substrate. 2. The stimulator recited in claim 1, wherein the antenna further comprises a plurality of connectors extending through the substrate and electrically connecting the upper coil to the lower coil. 3. The stimulator recited in claim 2, wherein the upper and lower coils are configured to overlap each other to position the turns of the coils overlapping each other, and wherein the connectors are configured to interconnect the overlapping turns of the upper and lower coils. . 4. The stimulator cited in claim 2, wherein the turns of the upper and lower coils are semicircular with opposite ends spaced apart, and where the connectors interconnect the overlapping ends of the turns of the upper and lower coils. 5. The stimulator recited in claim 4, wherein one of the upper and lower coils includes electrically conductive links that interconnect the first ends of the coil turns with the opposite second ends of the adjacent coil turns; and, optionally, where the electrically conductive links span a space between the opposite ends of the semicircular turns of the coil. 6. The stimulator cited in claim 5, wherein the other of the upper and lower coils is free of electrically conductive links, includes a first conductive wire electrically connected to a first end of the innermost coil turn, and a second conductive wire electrically connected to a second end of the outermost coil turn, where the first and second cables are configured to provide an electrical connection of the antenna with electronic components of the neuromuscular stimulator. 7. The stimulator cited in claim 1, wherein the antenna has a flexible printed circuit board construction, the substrate comprising a layer of polymeric material, the upper coil is created from a layer of conductive metallic material laminated onto a upper surface of the polymeric material, and the lower coil is created from a layer of copper conductive metal material laminated on a lower surface of the polymeric material; and, optionally, where the polymeric material is a polyamide material having a thickness of approximately 2 mil and the metallic material of the upper and lower coils is copper having a thickness of approximately 1.4 mil. 8. The stimulator cited in claim 1, wherein the upper and lower coils each have 8 to 12 coil turns and a pitch of 1.0 mm, or where the antenna has an outer diameter of 2 to 3 cm. 9. The stimulator cited in claim 1, wherein the antenna further comprises an outer coating made of a biocompatible material; or where the antenna is flexible and configured to conform to an anatomical structure at an implant point. 10. The stimulator cited in claim 1, further comprising an electronic package and a stimulation cable, wherein the antenna and the stimulation cable are electrically connected to the electronic package, the antenna is configured to supply electrical current to the electronic package to power the electronic package; the electronic package is configured to control the application of stimulation energy through the stimulation cable; and, optionally, wherein the stimulation cable comprises a plurality of electrodes, and the electronic package is configured to selectively control the operation of the electrodes to apply electrical stimulation and detect an EMG response. 11. The stimulator cited in claim 10, wherein the stimulation cable is configured to be bent with a desired shape and maintain that shape, in order to position the electrodes in relation to the neurological and/or neuromuscular structures when implanted. 12. The stimulator cited in claim 1, wherein the upper and lower coils, by virtue of being connected in parallel, are configured to produce the same induced voltage potential when subjected to an electromagnetic field. 13. An implantable stimulation system comprising: the stimulator of claim 1; and a controller comprising a control unit and a power mat containing one or more power transmission coils that can be excited to produce an electromagnetic field to induce electric current in the antenna and power the stimulator. 14. The implantable stimulation system cited in claim 13, further comprising a user interface composed of a computing platform, wherein the control unit is configured to communicate with the user interface so that the operation of the controller and of the stimulator can be controlled through the user interface. 15. The implantable stimulation system recited in claim 14, wherein: the user interface is configured to provide programming data for the stimulator to the controller, and the controller is configured to use the transmission coils to transmit the programming data to the stimulator, which receives programming data through the antenna; and the stimulator is configured to transmit data through the antenna to the controller, which receives the data through the transmit coils and transmits the data to the user interface.